Help with Basic Regular Expression Searchbrowsing

OK, folks, I’ve never used regular expressions before and it’s high time I started.

I’m trying to edit a large txt file that has text at the end of many lines that I want to completely remove. I was able to build a search expression to remove text (actually replace it with other text) at the beginning of the lines, but, removing the ending text is proving to be a bit more difficult. I’m sure there’s a way to do it via regexp but I’m not seeing it.

Each of the lines I want to edit has the same text in the middle of the line. I want to remove that text and the rest of the text all the way to the end of the line, preserving the CR/LF.